Table 1.
Comparing matched delta and alpha cases and controls for selected characteristics
| Delta variant N = 496 |
Alpha variant N = 496 |
Controls N = 4960 |
p value † | |||
|---|---|---|---|---|---|---|
| Delta vs. controls | Alpha vs. controls | Delta vs. Alpha | ||||
| Men | 274 (55.2%) | 274 (55.2%) | 2740 (55.2%) | Matching variable | ||
| Age category | ||||||
| 12 to 49 years | 354 (71.4%) | 354 (71.4%) | 3540 (71.4%) | Matching variable | ||
| 50 to 59 years | 76 (15.3%) | 76 (15.3%) | 760 (15.3%) | |||
| 60 to 69 years | 36 (7.3%) | 36 (7.3%) | 360 (7.3%) | |||
| 70 to 79 years | 18 (3.6%) | 18 (3.6%) | 180 (3.6%) | |||
| ≥ 80 yr | 12 (2.4%) | 12 (2.4%) | 120 (2.4%) | |||
| Number of previous contacts with NHS a | ||||||
| < 5 | 317 (63.9%) | 321 (64.7%) | 2893 (58.3%) | 0.0160 | 0.0058 | 0.7909 |
| 5 to 99 | 166 (33.5%) | 159 (32.1%) | 1775 (35.8%) | |||
| ≥ 100 | 13 (2.6%) | 16 (3.2%) | 292 (5.9%) | |||
| Users of selected drugs a b | ||||||
| Corticosteroids | 36 (7.3%) | 44 (8.9%) | 576 (11.6%) | 0.0034 | 0.0666 | 0.3511 |
| Drugs for chronic pain | 5 (1.0%) | 7 (1.4%) | 142 (2.9%) | 0.0150 | 0.0586 | 0.5614 |
| Oral anticoagulant agents | 2 (0.4%) | 2 (0.4%) | 98 (2.0%) | 0.0128 | 0.0128 | 1.0000 |
| Insulin | 6 (1.2%) | 8 (1.6%) | 94 (1.9%) | 0.2342 | 0.5766 | 0.5904 |
| Patients suffering selected diseases a b | ||||||
| Anaemias | 28 (5.6%) | 31 (6.3%) | 484 (9.8%) | 0.0027 | 0.0108 | 0.6873 |
| Chronic respiratory disease | 39 (7.9%) | 55 (11.1%) | 453 (9.1%) | 0.3464 | 0.1530 | 0.0831 |
| Dyslipidaemia | 30 (6.0%) | 23 (4.6%) | 404 (8.1%) | 0.0999 | 0.0055 | 0.3233 |
| Depression | 24 (4.8%) | 21 (4.2%) | 385 (7.8%) | 0.0184 | 0.0043 | 0.6473 |
| Hypertension | 29 (5.8%) | 28 (5.6%) | 362 (7.3%) | 0.2321 | 0.1730 | 0.8916 |
| Coronary and peripheral vascular disease | 28 (5.6%) | 23 (4.6%) | 351 (7.1%) | 0.2319 | 0.0404 | 0.4725 |
| Hypothyroidism | 12 (2.4%) | 10 (2.0%) | 190 (3.8%) | 0.1125 | 0.0403 | 0.6664 |
| Epilepsy and recurrent seizures | 4 (0.8%) | 5 (1.0%) | 155 (3.1%) | 0.0034 | 0.0077 | 0.7378 |
| Psychosis | 1 (0.2%) | 6 (1.2%) | 144 (2.9%) | 0.0004 | 0.0279 | 0.0579 |
| Diabetes without insulin therapy | 17 (3.4%) | 11 (2.2%) | 142 (2.9%) | 0.4761 | 0.4066 | 0.2503 |
| Malignancies | 4 (0.8%) | 6 (1.2%) | 139 (2.8%) | 0.0080 | 0.0355 | 0.5251 |
| Other diseases of the respiratory system | 3 (0.6%) | 6 (1.2%) | 136 (2.7%) | 0.0040 | 0.0410 | 0.3152 |
| Other diseases of the digestive system | 5 (1.0%) | 13 (2.6%) | 131 (2.6%) | 0.0261 | 0.9787 | 0.0571 |
| Other diseases of the genitourinary system | 3 (0.6%) | 3 (0.6%) | 130 (2.6%) | 0.0055 | 0.0055 | 1.0000 |
| Gout | 7 (1.4%) | 9 (1.8%) | 113 (2.3%) | 0.2094 | 0.5054 | 0.6143 |
| Autoimmune disease | 5 (1.0%) | 6 (1.2%) | 109 (2.2%) | 0.0774 | 0.1442 | 0.7618 |
| Other diseases of the circulatory system | 4 (0.8%) | 3 (0.6%) | 96 (1.9%) | 0.0739 | 0.0343 | 0.7045 |
| Symptoms, signs and ill-defined conditions | 0 (0.0%) | 2 (0.4%) | 96 (1.9%) | 0.0018 | 0.0143 | 0.1569 |
| Diseases of the skin and subcutaneous tissues | 4 (0.8%) | 3 (0.6%) | 82 (1.7%) | 0.1488 | 0.0722 | 0.7045 |
| Arrhythmia | 4 (0.8%) | 5 (1.0%) | 74 (1.5%) | 0.2201 | 0.3897 | 0.7378 |
| Inflammatory bowel diseases | 6 (1.2%) | 5 (1.0%) | 70 (1.4%) | 0.7149 | 0.4621 | 0.7618 |
| Other mental disorders | 0 (0.0%) | 0 (0.0%) | 69 (1.4%) | 0.0082 | 0.0082 | - |
| Heart failure | 2 (0.4%) | 5 (1.0%) | 64 (1.3%) | 0.0849 | 0.5917 | 0.2553 |
| Glaucoma | 5 (1.0%) | 6 (1.2%) | 58 (1.2%) | 0.7485 | 0.9366 | 0.7618 |
| Chronic kidney disease | 0 (0.0%) | 2 (0.4%) | 58 (1.2%) | 0.0155 | 0.1188 | 0.1569 |
| Severity of Covid-19 symptoms c | ||||||
| Asymptomatic | 122 (24.6%) | 122 (24.6%) | - | - | - | 0.6414 |
| Mild | 330 (66.5%) | 314 (63.3%) | - | - | - | |
| Severe | 37 (7.5%) | 51 (10.3%) | - | - | - | |
| Critical | 4 (0.8%) | 4 (0.8%) | - | - | - | |
| Fatal | 3 (0.6%) | 5 (1.0%) | - | - | - | |
† Chi-square test, or its version for the trend (categories of previous contacts with NHS and severity of Covid-19 symptoms)
aMeasured in the 2-years period before the index date
bItems have been sorted by decreasing frequency among controls. With respect to the complete investigated lists (please see Additional file 1: Table S3), only drugs used and diseases suffered by at least 1.0% of controls (i.e., by at least 50 negative-test citizens among the 4,960 ones included into the study) are reported
c Severity recognized at the index date. Source: https://www.COVID19treatmentguidelines.nih.gov/overview/clinical-presentation/#:~:text=Moderate%20COVID%2D19%20illness%20is,with%20moderate%20disease%20is%20recommended